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Controllability of orbiting solar reflectors under structural failures
Get PDFWith global demand for clean energy growing, the concept of utilising space-based assets to deliver energy services is gaining attention. Orbiting solar reflectors present one possible solution, where sun-light can be re-directed onto terrestrial solar power farms allowing their operational hours to be extended. Given the large size of these structures, they are vulnerable to impacts of micro-meteorites, or indeed space debris. Additionally, should some part of the structure fail, there can be an increase in their f lexibility, leading to questions over their controllability. This paper will investigate two types of structural failure: membrane degradation due to impacts which damage the reflective surface and joint failures in the structure. In the case of membrane degradation, a study is conducted into the resulting effect on desaturation schedules when the resulting asymmetry of the reflective structure leads to increased disturbance torques from solar radiation pressure. It will be shown that the highest rates of angular momentum accumulation occur when 50% of the membrane has been degraded, or damaged. A series of joint failures will then be studied. The increased flexibility of the structure, as a consequence of these failures, will lead to loss of controllability in all cases where actuation is limited by the capability of the overall structure to withstand control torques of up to 1750 Nm on each axis. If this constraint is removed, it will be shown that some cases of joint failures are still controllable by allowing higher control torques to meet the demands of the additional forces that increased flexibility of the structure brings to the system
Assessing hurricane-induced flood risks in urban areas using Bayesian networks and GIS applications
No full textIn the context of climate change, flooding presents a significant challenge for urban areas. The situation is worse with the increasing density of impervious surfaces and population. As an essential part of flood risk management, flood risk assessments can provide vital information to help local decision-makers and related departments formulate effective strategies. The indicator-based approach, an established method in hazard risk assessments, is widely used as it can allow for a systematic analysis of risk components. Although this approach is helpful, it is limited in handling new data and uncertainty in dynamic urban environments. To address these limitations, we developed a Bayesian network (BN) model based on an established indicator-based framework. This model allows for the dynamic incorporation of new evidence and provides explicit probabilistic quantification of uncertainties in the risk assessment process. This novel method combines the systematic analysis of the indicator-based approach with advanced computational capabilities to assess flood risks more dynamically. Data from eight historical flood events in Houston, USA, between 2000 and 2019 were used to train and test the BN model. By comparing the indicator-based approach and the BN model, 83.71% of the results were found to be identical. The flood assessment shows that during Hurricane Harvey, the western and northeastern regions of Houston faced the highest flood risks, while the central areas experienced relatively lower flood risks. In addition, the sensitivity analysis shows that three nodes under the exposure part, the exposed population, exposed forest, and exposed water area, are the most impactful factors
Balancing preference and practicality: student choice of study mode in a hybrid-flexible academic writing course
No full textHow – and why – do students engage with an increasingly diverse range of learning opportunities in the digitised university? This paper investigates students’ motivations for choosing in-person, online or asynchronous study modes and explores the implications for academic writing provision. I reflect on student and teacher experiences on a non-credit, Masters-level academic writing course at a UK university which was delivered through a ‘hybrid-flexible’ approach (Beatty, 2019). Students could opt to learn through synchronous in-person (on-campus) classes, synchronous online classes or asynchronous activities delivered through a virtual learning environment; all study modes supported the same learning outcomes and students could switch between them as they choose. Course evaluations reveal students have different motivations for choosing in-person, online or asynchronous learning, and suggest that learning preference and practical motivations are not always aligned. I reflect on the opportunities and challenges I encountered as a teacher designing and delivering hybrid-flexible academic writing content. I conclude by exploring how tensions between learning preference and practical motivations might be addressed in the design and delivery of in-person, online and asynchronous learning activities
Straight Out the Scheme. Youth Work Resource created by the Wise Men with support from Fern Gillon and Alistair Fraser
Get PDFThe resource pack is made up of four creative resources, each accompanied by a session plan, providing guidance about the content and suggested activities to accompany the resource. The resources are designed to be used by anyone working with young people in both educational and community settings.
The resources can be used either as one-off topic specific sessions, or used together drawing on a range of central themes linked to the issue of youth violence, including social media, substance misuse, relationships and making change.
All young people are different, and it’s likely that every group of young people will need some adjustments to the session plans, dependent on their particular needs, interests, strengths and vulnerabilities. However, these resources have been designed broadly with young people aged 12+ in mind
Conformational isomerism tunes barocaloric potential of MIL-53(Ga)-fum frameworks
Get PDFWith the negative implications of current refrigerants on the environment, there is a necessity for greener alternatives. Solid-state caloric materials exhibit large entropy and temperature changes that avoid liquid-vapour transitions of current refrigerants. Through guest adsorption, flexible metal-organic frameworks (MOFs) exhibit large entropy changes under small applied pressures, making them promising candidates. Though effective, flexible MOFs lack long-term mechanical stability owing to the mechanical stress induced during operation. Herein, we highlight and categorise the previously unexplored conformational isomerism of the MIL-53( X )-fum frameworks, which originates from the relative orientations of the fumarate linkers, and explore the effect on structural flexibility and barocaloric potential. Using single crystal X-ray diffraction (SCXRD) and ab initio molecular dynamics (AIMD), we reveal the third and final possible conformational isomer, MIL-53( X )-fum( c ), to complement the two previously reported (MIL-53( X )-fum( a ) and MIL-53( X )-fum( b )), and investigate the effects of the isomerism on the framework properties. We uncover the isomerically unique mechanical stability of MIL-53(Ga)-fum( c ) through simulated potential energy surfaces and find that the vacated open phase has exceptional thermal stability of up to 650 K. Through grand canonical Monte Carlo (GCMC), the reversible adsorption-driven entropy changes under 0.4 MPa of applied pressure were calculated to be Δ S = 186.2 J K -1 kg -1 and 151.8 J K -1 kg -1 for the adsorption of H 2 O and CO 2 , respectively. The results of our studies suggest that MIL-53(Ga)-fum( c ) can exhibit a caloric response that is competitive with current commercial refrigerants. Furthermore, we outline the significance of exploring conformational isomerism in MOFs to increase the space in which materials discovery can occur
Evaluating the use of serum total solids to predict serum IgG in Holstein and Angus crossbred calves
Get PDFThis study evaluated the use of serum total solids (STS) to assess passive immunity in Holstein and Angus cross Holstein calves. The objectives of our study were 1) to determine if STS and serum IgG differs between Holstein and Angus cross Holstein (Angus X) newborn calves 2) to compare the relationship between STS and serum IgG in both breeds and 3) to determine if the industry recommended passive immunity STS cutpoint (>62g/L) for predicting serum IgG concentration ≥25g/L is appropriate for Angus X calves. This observational study was part of a wider clinical trial where calves were randomized to colostrum IgG doses ranging from 200 to 350g. Blood samples were taken from calves at 2 d of age, and the separated serum was tested for STS (g/L) using optical refractometry. The remaining serum was stored frozen at −20°C and tested 2 weeks later for IgG concentration (g/L) using radial immunodiffusion (RID). Multivariable linear regression models were used to compare serum IgG and STS between breeds, controlling for colostrum IgG dose and calf sex. Pearson correlation coefficient and linear regression models were used to compare correlations between serum IgG and STS by breed. Area under the curve (AUC) and diagnostic sensitivity (Se) and specificity (Sp) were used to measure the ability of STS to identify calves with serum IgG ≥ 25g/L. The number of calves analyzed in the final data set from each group were 272 Holstein and 119 Angus X. Although serum IgG was similar between breeds, Holstein calves had 3.1g/L (95% CI: 1.7, 4.5) higher STS than Angus X calves. The AUC of STS for predicting IgG ≥ 25g/L was the same for both breed groups (AUC = 0.86). A previously recommended cutpoint of 62g/L STS had Se and Sp of 51% and 91%, respectively, when predicting serum IgG ≥ 25g/L in Holsteins. We found that a STS cutpoint that was 3g lower (59g/L) in Angus X calves provided similar performance (Se 55%, Sp 94%). And although colostral IgG absorption is similar between breeds, the relationship between serum IgG and STS differs, likely due to Angus X calves having a lower concentration of non-IgG proteins in serum. Although we acknowledge that the sensitivity of these cutpoints are low, we believe that breed specific thresholds may be necessary to predict a calf serum IgG ≥ 25g/L for Angus X calves, compared with the > 62g/L recommendation proposed for Holsteins in the literature
Active learning in politics and international relations
No full textActive learning is central to the teaching of Politics and International Relations. This symposium brings together a series of short teaching notes that seek to advance our understanding of effective, engaging teaching practices and their ability to cultivate active learning. This introduction provides a brief overview of active learning within the pedagogy of the field and introduces the four teaching notes in the symposium
Threads of Empire: Modes, Materials, and the Making of Textiles
No full textThis blog discusses a workshop on global textile history held at the University of Glasgow on 8-9 September 2025 and partly funded by the Economic History Society
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